Starting with version 4.0, Builder theme is responsive.
Widget Content Editor
The Widget Content feature adds the use of an advanced editor to create widget content. A new Widget Content top-level menu is now on the back-end and allows for creation of widget content with the same interface as posts and pages. Once a Widget Content entry is saved, you can add the Widget Content widget to a sidebar location and select the desired Widget Content entry from the drop down to add that content to a sidebar.
Builder provides the ability to easily export Layouts and Views and/or Theme Settings and import them to another site running Builder.